When measuring the temperature of a medium in a container or pipe, the problem often arises of the interior of the container or the pipe not being accessible for the measurement. The medium may, for example, be so aggressive or at such a high pressure that a sensor in the container or in the pipe would be destroyed. Therefore, in such cases the temperature is measured using a temperature sensor that is arranged on the outside of a wall of the container or pipe.
In particular for aggressive media or high pressures, a certain minimum wall thickness is however required which prevents the heat from passing therethrough to a sensor that is arranged on the outside of the wall. The measurement results are therefore often very imprecise.